May 16, 2007

Inexpensive, universal, super nanoglue

A new method allows a self-assembled molecular nanolayer to become a powerful nanoglue by "hooking" together any two surfaces that normally don’t stick well.

Unprotected, a nanolayer (green ball: silicon, blue: sulphur, red: carbon, white: hydrogen) would degrade or detach from a surface when heated to 400 degrees Celsius. But when topped with a thin copper film that binds strongly with the nanolayer, heat causes the nanolayer to form strong chemical bonds to the silica underlayer -- hooking or gluing the copper-silica "sandwich" together. This technique produces a sevenfold increase of the thin film sandwich’s adhesion strength and allows the nanolayer to withstand temperatures of at least 700 degrees Celsius. Both features are unexpected and unprecedented. This new ability to bond together nearly any two surfaces using nanolayers will benefit nanoelectronics and computer chip manufacturing. Other envisioned applications include coatings for turbines and jet engines, and adhesives for high-heat environments.

Because of their small size, these enhanced nanolayers will likely be useful as adhesives in a wide assortment of micro- and nanoelectronic devices where thicker adhesive layers just won’t fit.

Another unprecedented aspect of Ramanath’s discovery is that the sandwiched nanolayers continue to strengthen up to temperatures as high as 700 degrees Celsius. The ability of these adhesive nanolayers to withstand and grow stronger with heat could have novel industrial uses, such as holding paint on hot surfaces like the inside of a jet engine or a huge power plant turbine.

“The molecular glue is inexpensive – 100 grams cost about $35 – and already commercially available, which makes our method well-suited to today’s marketplace. Our method can definitely be scaled up to meet the low-cost demands of a large manufacturer,” he said.